1. Field of the Invention
This invention relates to a method for remotely diagnosing copy quality defects in system reprographic machines or other digital copiers.
2. Description of Related Art
In system reprographic machines, or digital copiers in general, a document or series of documents comprising at least one print job are successively scanned. Upon scanning of the documents, image signals are obtained and electronically stored. The signals are then read out successively and transferred to a printer for formation of the images on paper. Once a document is scanned, it can be printed any number of times or processed in any number of ways (e.g., words deleted or added, image magnified or reduced). If a plurality of documents comprise a job that is scanned, the processing or manipulation of the scanned documents can include deletion of one or more documents, reordering of the documents into a desired order, or the addition of a previously or subsequently scanned document. The printing or processing can be relatively synchronous with scanning or asynchronous after scanning.
If asynchronous, a time interval exists between scanning and printing or processing. The system can then accumulate a number of scanned jobs in the system memory for subsequent processing or printing. The order of the jobs to be printed may be different from the order of the jobs as scanned depending on the priority of the jobs and the desires of the operator for increasing productivity or throughput and decreasing printer or scanner down time.
However, even system reprographic machines need occasional alignment or correction of copier components. Further, mechanical problems in paper handling (i.e., skew, delayed feed and the like) as well as incorrect placement of transparencies can also adversely affect copy quality. Copy quality variation both within a reproduction machine and within a machine population is a major concern. Known methods of correction or calibration require extensive operator interaction or they provide inadequate correction.
Over time and through extended use, the subsystems of a system reprographic machine gradually wear, become contaminated, or slip out of adjustment. Because so many of the subsystems, for example, the printer and illumination subsystems are interrelated and dependent upon each other, errors or degradation of any of these components affects the operation and quality of the other components, usually propagating the errors. Due to this interrelationship, it is often difficult to determine the root cause of a copy quality error or to isolate one subsystem's error from errors affecting other components.
Typically, most copy quality problems can only be resolved by a trained service representative. The service representative is called and must invariably travel to the customer's location, inspect the defect(s) in copy quality and then make adjustments to the customer's machine. For more difficult problems, the service representative may have to consult with other experts to finally diagnose the problem.
There are several disadvantages to the typical telephonic service call initiated by the operator at the machine location. First, it is unlikely that the service representative will know the cause of the problem before arriving at the customer's location, which means that it is possible that the service representative will not have the proper parts to correct the problem. Second, the amount of training and experience necessary to make a correct diagnosis on the first attempt, is considerable (and expensive). Finally, difficult problems may require considerable time to diagnose and repair, particularly if engineering must be consulted, which contributes to customer dissatisfaction.
Recently, however, systems for monitoring the operation of a plurality of reprographic machines from a remote source by use of a powerful host computer having advanced, high level diagnostic capabilities have been developed. These systems have the capability to interact remotely with the machines being monitored to receive automatically initiated or user initiated requests for diagnosis and to interact with the requesting machine to receive stored data to enable higher level diagnostic analysis. Such systems are disclosed in U.S. Pat. No. 5,038,319 and 5,057,866 (the disclosures of which are incorporated herein by reference), owned by the assignee of the present invention. These systems employ Remote Interactive Communications (RIC) to enable transfer of selected machine operating data (referred to as machine physical data) to the remote site at which the host computer is located, through a suitable communication channel. The machine physical data may be transmitted from a monitored document system to the remote site automatically at predetermined times and/or in response to a specific request from the host computer. Machine physical data may also be transmitted upon operator instruction or when a problem severity threshold is reached.
In a typical RIC system, the host computer is linked by a public switched telephone system or a combination of public and dedicated systems to local reprographic machines via modems. The host computer may include a compiler to allow communication with a plurality of different types of machines and an expert diagnostic system that performs higher level analysis of the machines physical data than is available from the diagnostic system in the machine. After analysis, the expert system can provide an instruction method which can be used by the machine operator at the site of the document system to overcome a fault. Alternatively, if the expert system determines that more serious repair is necessary or a preventive repair is desirable, a message is sent to a local field work office giving the identity of the machine and an identification of the type of service action required.
Importantly, however, such expert systems, resident in a remote host diagnostic computer and accessed via RIC, have never been used to diagnose and correct copy quality defects. Thus, there is need of a method for remotely diagnosing copy quality defects in system reprographic machines and digital copiers.